What is a function that hair does NOT perform?

Hair serves several important functions in the body, contributing to protection, thermoregulation, and sensory perception. However, the specific function of trapping sweat to enhance heat loss does not accurately describe the role of hair.

Hair primarily helps to regulate body temperature by providing insulation—this is especially prominent in animals with thicker fur. While hair can play a minimal role in heat regulation, it does not actively trap sweat to promote heat loss; instead, sweat evaporates off the skin's surface, with hair potentially acting as an insulating barrier. Thus, while humans do lose heat through sweat, the primary function of hair is not to facilitate this process.

In contrast, hair plays significant roles in the other options. It provides insulation, protecting against heat loss, and serves to protect the scalp from damaging UV radiation by acting as a physical barrier. Hair is also rich in nerve endings, contributing to sensory perception, enabling the detection of light touch and changes in the environment.